Language/Types/Interface_Types/subtype_t48.dart

/*
 * Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 * for details. All rights reserved. Use of this source code is governed by a
 * BSD-style license that can be found in the LICENSE file.
 */
/**
 * @assertion A type T is more specific than a type S, written T << S, if one
 * of the following conditions is met:
 *  • T is S.
 *  • T is ⊥
 *  • S is dynamic.
 *  • S is a direct supertype of T.
 *  • T is a type parameter and S is the upper bound of T.
 *  • T is a type parameter and S is Object.
 *  • T is of the form I<T1, ..., Tn > and S is of the form I <S1, ..., Sn>
 *    and Ti << Si 1 <= i <= n.
 *  • T and S are both function types, and T << S under the rules of section
 *    (Types/Function Types).
 *  • T is a function type and S is Function.
 *  • T << U and U << S.
 * << is a partial order on types. T is a subtype of S, written T <: S, iff
 * [⊥/Dynamic]T << S.
 * . . .
 * An interface type T may be assigned to a type S, written T <=> S, if either
 * T <: S or S <: T.
 * @description Checks that if T and S are both function types and T << S then
 * the interface type T << the interface type S.
 * @static-clean
 * @author ilya
 */
import "../../../Utils/expect.dart";

typedef void F1(int i, String s, [int p]);
typedef void F2(int i, String s, {int n});

class Whatever {}

main() {
  void f11(int i, String s, [int p]) {}
  Expect.isTrue(f11 is F1);

  int f12 (int i, String s, [int p]) {}
  Expect.isTrue(f12 is F1);

  int f13 (int i, [String s, int p]) {}
  Expect.isTrue(f13 is F1);

  int f14 (int i, [String s, int p, Whatever w]) {}
  Expect.isTrue(f14 is F1);

  //---

  void f21(int i, String s, {int n}) {}
  Expect.isTrue(f21 is F2);

  void f22(int i, String s, {int n}) {}
  Expect.isTrue(f22 is F2);

  int f23 (int i, String s, {int n, int n2}) {}
  Expect.isTrue(f23 is F2);

  int f24 (int i, String s, {int n, Whatever w}) {}
  Expect.isTrue(f24 is F2);
}